1. Department of Orthopaedic Surgery, LKH Klagenfurt, A-9020 Klagenfurt, St. Veiter Strasse 47, Carinthia, Austria.
2. AO Research Institute, Clavadelerstrasse 8, CH-7270 Davos Platz, Switzerland.
3. Biomechanics Section, TU Hamburg-Harburg, Denickestrasse 15, D-21073, Hamburg, Germany.
4. Rush University Medical Center, 1653 W. Congress Parkway, AcFac 726b, Chicago, Illinois 60612, USA.